The tense of a sentence denotes a time, whether it is the time now (present), time then (past) or the time to come (future). The verb of a sentence has most to do with the tense. In the given sentence, we need to fill in a word that determines the correct tense. When a sentence is in the negative, the main verb itself doesn't change its form, but a negative word 'not' precedes the main verb and follows the first helping verb, the verb now consists of two or more words, where the other verb/s are called the helping verb/s, did not go, did not see, has not written, etc. The given sentences are in the negative, the movie wasn't good, hence the speaker did not enjoy it. The speaker refers to an action that completed in the past, hence a verb in the simple past tense is required. 'Did not enjoy', contracted as 'didn't enjoy' is in the past tense, 'did' is the helping verb that refers to a time in the past, hence option B is correct. 'Enjoyed' is also in the simple past tense, but it's in the affirmative, whereas the sentence is in the negative, hence option A is incorrect. 'Didn't enjoyed' is grammatically incorrect, 'did' is already performing the function of a helping verb by referring to the past tense, hence option C is incorrect. 'Wasn't enjoy' is also grammatically incorrect, 'wasn't' is used in the past continuous tense 'wasn't enjoying', whereas the sentence is in the simple past tense, hence option D is incorrect.